Background: Peritonitis is a common complication of peritoneal dialysis (PD) and is associated with significant morbidity. Adequate treatment is essential to reduce morbidity and recurrence. Objectives: To evaluate the benefits and harms of treatments for PD-associated peritonitis. Search strategy: We searched the Cochrane Renal Group's specialised register, the Cochrane Central Register of Controlled Trials (CENTRAL, in The Cochrane Library), MEDLINE, EMBASE and reference lists without language restriction. Date of search: February 2005 Selection criteria: All randomised controlled trials (RCTs) and quasi-RCTs assessing the treatment of peritonitis in peritoneal dialysis patients (adults and children) evaluating: administration of an antibiotic(s) by different routes (e.g. oral, intraperitoneal, intravenous); dose of an antibiotic agent(s); different schedules of administration of antimicrobial agents; comparisons of different regimens of antimicrobial agents; any other intervention including fibrinolytic agents, peritoneal lavage and early catheter removal were included. Data collection and analysis: Two authors extracted data on study quality and outcomes. Statistical analyses were performed using the random effects model and the dichotomous results were expressed as relative risk (RR) with 95% confidence intervals (CI) and continuous outcomes as mean difference (WMD) with 95% CI. Main results: We identified 36 studies (2089 patients): antimicrobial agents (30); urokinase (4), peritoneal lavage (1) intraperitoneal (IP) immunoglobulin (1). No superior antibiotic agent or combination of agents were identified. Primary response and relapse rates did not differ between IP glycopeptide-based regimens compared to first generation cephalosporin regimens, although glycopeptide regimens were more likely to achieve a complete cure (3 studies, 370 episodes: RR 1.66, 95% CI 1.01 to 3.58). For relapsing or persistent peritonitis, simultaneous catheter removal/replacement was superior to urokinase at reducing treatment failure rates (1 study, 37 patients: RR 2.35, 95% CI 1.13 to 4.91). Continuous IP and intermittent IP antibiotic dosing had similar treatment failure and relapse rates. IP antibiotics were superior to IV antibiotics in reducing treatment failure (1 study, 75 patients: RR 3.52, 95% CI 1.26 to 9.81). The methodological quality of most included studies was suboptimal and outcome definitions were often inconsistent. There were no RCTs regarding duration of antibiotics or timing of catheter removal. Authors' conclusions: Based on one study, IP administration of antibiotics is superior to IV dosing for treating PD peritonitis. Intermittent and continuous dosing of antibiotics are equally efficacious. There is no role shown for routine peritoneal lavage or use of urokinase. No interventions were found to be associated with significant harm.